BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Vesper Sparrow In Northern Rockies

All regionsNorthern RockiesGrassland birds

Vesper Sparrow in Northern Rockies has risen sharply: up 59% on the route-weighted index since 1970.

+59%Since 1970TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
188Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Vesper Sparrow has risen sharply in Northern Rockies: up 59% on the route-weighted index since 1970.

Vesper Sparrow In Northern Rockies Population Forecast

If the recent trend holds, Vesper Sparrow in Northern Rockies is projected to stay roughly flat through 2030, near 17 (95% range 13–22). A 5-year backtest shows a typical error of ±11.7%, with 80% of held-out values landing inside the 95% band.

+0%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
17Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
13–2295% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±11.7%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Vesper Sparrow in Northern Rockies is projected to stay roughly flat through 2030, near 17 (95% range 13–22). A 5-year backtest shows a typical error of ±11.7%, with 80% of held-out values landing inside the 95% band.19682030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
2026171322
2027171322
2028171322
2029171322
2030171322

Routes In Northern Rockies

Routes recording Vesper Sparrow in Northern Rockies.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
BoulderMONTANA1142025
Saleratus CrUTAH862018
Freeman CreekMONTANA812016
Big SandyWYOMING772025
LeoWYOMING762025
BeaverheadMONTANA752025
Heart ButteMONTANA732025
PolsonMONTANA702025
Great DivideCOLORADO692025
BairoilWYOMING682025
AugustaMONTANA642025
BoulderWYOMING622025
Neponset ResUTAH612018
Seedskadee 2WYOMING612024
ArmintoWYOMING602025
NowoodWYOMING582025
MeeteetseWYOMING582025
St MaryMONTANA572008
St. Mary 2MONTANA542025
Fort LoganMONTANA542025
RyegrassWYOMING512025
Willow Creek 2MONTANA502025
Muddy CreekMONTANA492015
ClarkWYOMING472025
Ne EntranceWYOMING462025

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.